Adolescence is a developmental period characterized by increased emotional volatility and reported stress, and relatedly, is also the typical age of onset for many psychiatric mood disorders. Concurrently, the social lives of adolescents change and expand reflecting increased independence and preparation for adulthood. While the emotional and social changes that take place during adolescence are well documented, less research has examined the relationship between the two, or in other words, how do social forces shape emotions? To address this gap in the literature, this proposal will take a developmental cognitive neuroscience approach to examine mechanisms underlying the relationship between social and emotional processing during adolescence. Aim 1 will examine how social influence shapes responses to negative situations during adolescence compared to adulthood. This aim is meant to address the observed increase in negative mood states that take place during adolescence. Aim 2 will measure how social influence shapes responses to primary rewards during adolescence compared to adulthood. This aim will address the heightened reward response observed in adolescents compared to adults. By investigating the impact of social feedback in both aversive and appetitive affective domains, our goal is to (a) explore the power of social influence in changing affective responses and (b) uncover the behavioral and neural mechanisms supporting these changes. By closely examining the relationship between social and emotional changes that take place during adolescence with a scientific lens, this proposal will contribute to basic research on adolescent development, and can inform efforts to improve teen-focused mental health practices and public health interventions.